流行病學

To flow, move, or drift; to circulate or spread; a stream; a class or grade; to banish or exile.

To walk, go, travel, move; to do, perform, capable; behavior, conduct; a line, row; a trade, profession; a business firm; a measure word for rows or lines.

illness; disease; to fall ill; defect; to be sick; to worry about.

To learn or study; to imitate or mimic; knowledge or learning; a school or place of education; a school of thought or doctrine.